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Discussion Starter #1
Hello, I am building two Rythmik Audio 15 inch subwoofers. I am at the point in the build where I am close to attaching the subs to the box. I am wondering what is the best way? Just deck screws? I have read about t-locks or something like that. Do you know where they come from and are they better? The subs are down firing and recessed inside of a 3/4 inch MDF board. The sub itself will be mounted to a 3/4 inch MDF board. Thanks for your help! Dan
 

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Discussion Starter #6
Wow. thanks for the help as well as the links also. I went to home depot and they had no idea what a t-nut is, however the speaker mounting kit seems very nice (link earlier in the thread). Yes, I do have pics. I am taking pics of the whole process. Been at it for the last week and a half. Probly have about a week or more left. I am very excited. I currently have two 12 inch DIY subs I built about 10 years ago. I made them look like greek columns. After I have 5 posts I will post pics of them.
 

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Discussion Starter #9
So the hurricane nut goes inside the enclosure and the bolt goes from the outside through the speaker, through the MDF and then through the hurricane nut? Is that the right idea?
 

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The best ever was the screws that TC sounds included with their drivers. They were a deep thread, lots of bite. Somewhere on the web I found some internal wrenching lag bolts that were similar, and I guess I did not save the site. They were maybe on madisound or a similar place like that. Drill a small pilot hole, and sink them in. Then pull them out, and the driver, and harden the threads with a few drops of ca glue. (Have LOTS of that left over from my rc airplane days) Then re-mount.
I swore up and down last night when I spun the hurricane nut. I wish like you know what that I tried to find those lag bolts. The ones that tc sounds had were apparently custom made. As far as I am concerned, someone could get them made, and I would pay a buck a screw. They are worth it. Maybe more.

The one that spun last night. It was a bad few minutes, holding on to a 60 pound driver, and trying to pull on the bolt to get it to hang up enough to un thread the bolt. I finally got it free, and mixed up some jb weld to re- seat it. All is good now, and all bolts tight, but I really don't ever want to find out by having to remove the sub again. I did not glue the nuts in to begin with. Maybe I should have.
 

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If you just want to screw directly into the MDF you might look at these screws as it seems they have pretty deep threads. It says no predrilling required but I still would.

http://www.ultimategarage.com/spax.html

The pan head and washer head look like they might be suitable for holding drivers in if you got big enough ones.

Another common thing I have seen is for people to cut little squares of plywood and glue them to the backside of the faceplate where the driver screws will go in since plywood has such good screw holding characteristics.
 

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Incase anyone missed it David D at htguide wrote a really great thread about putting a dab of gorilla glue on your T-nut before you put it in. It upped the holding power SUBstantially. I remembered that earlier today before I put my 12 in the el-cheapo sub that I am working on right now so I ran to the Home Depot and picked up some gorilla glue and dabbed it on the t-nuts before I put them in. So far seems to have worked great, and I just went into the MDF, no plywood involved.

Just be careful the stuff is nasty and expands like crazy, normally I hate it but for this application, used sparingly it seems to work wonders.

Here is a link to the thread showing the use of gorilla glue on t-nuts.
http://www.htguide.com/forum/showthread.php4?t=29922
 

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Good call, one of the advantages of drawing them in with a bolt vs pounding in or pressing in, is that if the threads are screwed up you won't be able to get them in.
 

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Discussion Starter #17
Thanks for all the input. I think that I am going to go with the first suggestion. The last subs I built were about 12 years ago. I never once had to open the enclosure, so I will hope I have the same luck this time. Plus, my driver is not 60 pounds! Hello! I did not even know they made sub speakers that heavy!
 

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Does anybody use the foam seal tape around the edge of their sub before mounting them? Or is this just something used for sealed subs?
 

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Discussion Starter #19
My understanding is that a sealed enclosure sub box should be air tight. For whatever reason my DIY kit (from Rythmik) did not include anything, but I am convinced that if I simply attach the sub it will not pass the 'pushing on the cone' test where it should fight you back and not slowly receed into the box. I went to Home Depot and bought some regular weather stripping stuff that was 1/8 th thick. Hopefully it will do the trick.
 

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Yes, you want it sealed very well but not a perfect hermetical seal. If you seal too well, the difference in barometric pressure between the inside and outside will cause the cone to have a pressure bias as weather changes and also when the air inside the box heats. I recall seeing a thread here where someone noticed their cone was slightly in with no signal.
 
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